1. Technical Field
This invention relates to the field of projection television receivers utilizing liquid crystal on silicon (LCOS) technology in the light projection system, and more particularly, to a contour reduction method and system suited for an LCOS high definition television (HDTV) receiver.
2. Description of the Related Art
A light engine utilizing liquid crystal on silicon (LCOS) technology has a severe non-linearity in the display transfer function. This non-linearity can be corrected with a digital lookup table, referred to as a gamma table. The gamma table, however, has limited resolution, resulting in consecutive input values producing the same output values (repeated states) in low gradient portions of the table. Some of the repeated states are repeated three times, producing noticeable, undesirable contouring in the pictures made by the display.
LCOS technology is a recent development. In consequence, there is little prior art in the field. Generally, the brute-force solution has been employed to correct the non-linearity. Specifically, the brute-force solution has been to use a gamma table with enough resolution to accommodate the non-linearity. In some cases, for example, 10-bit values stored in the gamma table would have to be increased by two bits, from 10 bits up to 12 bits. The resolution of the table, however, is often under the control of the imager supplier. In consequence, the resolution of the table is not easily or quickly changed. There is a clear need for a method and/or apparatus to increase the resolution, or at least the apparent resolution, of such gamma tables without time consuming and costly design efforts.